The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Many video coding standards include dividing an image frame of an input video into one or more coding units. In general, a coding unit may include a prediction unit that has a luma prediction block and at least two corresponding chroma prediction blocks. When encoding an original image of a block, the original image can be divided into a predicted image and a residual image of the block according to a predetermined video coding standard. When decoding the block, a reconstructed image of the block can be obtained by generating and combining the predicted image and the residual image of the block according to the same predetermined video coding standard.
In some applications, the predicted image of a block can be generated based on the image(s) of other blocks and/or other frames. Such prediction scheme is also known as inter-prediction. In some applications, the predicted image of a block can be generated by extrapolating neighboring samples adjacent to the block based on a selected one of plural prediction modes. Such prediction scheme is also known as intra-prediction. The plural prediction modes for intra-prediction may include extending the neighboring samples along one of plural predetermined direction (also known as directional prediction modes), assigning an average value of the neighboring samples to all pixels of the block (also known as a direct current (DC) prediction mode), or performing a two-dimensional extrapolation based on the neighboring samples adjacent to different sides of the block (also known as a planar prediction mode).